And on the same subject, quoting the tvtropes article linked above:
> Ironically, in a major sense-of-humour failure, Monty Python founder Eric Idle threatened to sue an independent film-maker who used the "that's not a horse - you're using coconuts!" gag, claiming he had originated it for Monty Python and the Holy Grail. Saner counsel prevailed, when it was pointed out to him exactly how old the gag was, and that (for instance) a radio comedy show Idle himself had written for had used this gag way back in the 1960's - ten years before the Holy Grail movie. And the BBC radio comedy archives preserved older examples still...
> Ironically, in a major sense-of-humour failure, Monty Python founder Eric Idle threatened to sue an independent film-maker who used the "that's not a horse - you're using coconuts!" gag, claiming he had originated it for Monty Python and the Holy Grail. Saner counsel prevailed, when it was pointed out to him exactly how old the gag was, and that (for instance) a radio comedy show Idle himself had written for had used this gag way back in the 1960's - ten years before the Holy Grail movie. And the BBC radio comedy archives preserved older examples still...